The new BMW M4 Convertible goes on sale this September, with prices starting from £60,730.

The M4 Convertible features a wider body and a longer wheel-base than its M3 Convertible predecessor.

Its three-part folding metal roof is both quieter and warmer in winter, and can be folded away completely in 20 seconds, an operation that can be performed at speeds of up 8 mph.

The boot offers 370 litres of space, falling to 220 litres with the roof folded, although a six-second ‘loading’ mode offers greater access.

Power comes from the same 3.0-litre in-line six-cylinder twin-turbo engine as the M3 Saloon and M4 Coupe.

This unusually high-revving unit has a 7,600rpm red-line and develops 431hp and 550Nm of torque, enough to achieve the 0-62mph sprint in 4.4 seconds when mated to the seven-speed dual-clutch transmission, or 4.6 seconds with a conventional manual ‘box.  Top speed is electronically limited to 155mph.

This level of power necessitated the use of additional water, engine oil and transmission oil coolers, plus an electric coolant pump to help cool the turbocharger bearings when the car comes to a stop.

A six-speed manual transmission is standard, while the M DCT unit is a £2,645 option that allows gear-shifting either via the gear lever or steering wheel-mounted paddles, and incorporates a launch control feature.

BMW say the use of aluminium for the bonnet, front wings and other components, plus the selection of a carbon-fibre reinforced plastic propeller shaft and strut brace, have contributed to a 60kg weight reduction compared to the old M3 Convertible.

This weight reduction, plus the use of aerodynamic measures such as the smooth underbody and special airflow channels at the front, are said to be key contributors to the M4’s economy figure of 32.5 mpg and CO2 emissions of 203 g/km (31 mpg and 213 g/km for manual models).

Of course, the M4 Convertible’s focus is on the driving experience rather than its eco-credentials, and the M4 uses a double-joint sprint strut suspension at the front and an aluminium five-link axle at the rear.

An Active M Differential helps keep everything in check, particularly when accelerating hard out of corners, and can provide a variable degree of lock up to 100% when required.

All UK models will be fitted with Adaptive M suspension as standard, and this offers a choice of Comfort, Sport and Sport+ modes that also alter the settings for the electro-mechanical steering rack.

UK standard specific will also include 19-inch light alloy wheels, BMW Professional infotainment system, front and rear parking sensors, folding door mirrors and heated leather seats.